Browsing by Author "Anil Ö."
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Item Effect of concrete compressive strength variation on impact behaviour; [Beton dayanimindaki̇ deǧi̇şi̇mi̇n çarpma davranişina etki̇s](2011) Kantar E.; Arslan A.; Anil Ö.The least well known loading type is the impact loading that are affecting on to RC structures. For these reason an experimental study is conducted, and the effect of concrete compression strength variation on impact behavior of concrete investigated. Total ten beam specimens at which five of them are manufactured with normal compression strength concrete without reinforcement are prepared. Remaining five had high concrete compression strength. These specimens are tested under the impact loading that is applied by dropping constant weight hammer from five different heights. The acceleration due to impact loading is measured against time. The change of velocity, displacement and energy are calculated for all specimens. The failure modes of the specimens with normal and high concrete compression strength are observed under the loading of constant weight impact hammer that are dropped from different heights. The increase in compression strength of concrete is significantly affected on the impact behaviors of the specimen, and as the compression strength increase impact behavior improved. Dissipated energy, the number of the hammer drops, and accelerations are increased, and displacement is dropped.Item Evaluation of blast-induced ground vibration effects in a new residential zone(2013) Dogan O.; Anil Ö.; Akbas S.O.; Kantar E.; Tuǧrul Erdem R.The results from an experimental blasting program that was performed at the special explosives training field of the General Directorate of Security in Ankara, where new residential blocks are planned to be constructed nearby, are presented. With the objective of estimating the blast-induced ground vibration effects on the proposed structures, various blasting parameters of nineteen surface and underground explosions were recorded in two directions at three measurement stations. Site-specific empirical relationships between peak particle velocity, the amount of explosive and the distance were developed. These relationships were used to construct a practical blasting chart, which gives the maximum amount of explosive to be used as a function of distance, for future underground and surface blasting operations in the training field. Since the use of peak particle velocity in the field of civil engineering has been limited so far, site-specific parameters were also estimated to predict the blast-induced horizontal peak ground acceleration. Then, an attempt was made to investigate the dynamic responses of four and six storey reinforced concrete structures that consist of frame and shear wall type structural systems under the measured accelerations using finite element analysis. The limitations of this approach were discussed within the context of damage estimation. © 2013 Elsevier Ltd.Item Load displacement behavior of concrete beam under monotonic static and low velocity impact load(Iran University of Science and Technology, 2014) Yilmaz M.C.; Anil Ö.; Alyavuz B.; Kantar E.Experiments were carried out to observe the influence of loading type on concrete beam specimens. Beam specimens made of similar concrete mixture with the same geometry were tested under three point static loading and low velocity drop weight impact loading. Load – displacement behavior, absorbed energy dissipation capacity, stiffnesses, failure modes of beam specimens were obtained and discussed. A finite element (FE) model was prepared in ANSYS Explicit STR software and the results of FE analysis were compared with experimental results. The loading type and loading rate havesignificant influence on the maximum load, stiffness and energy dissipation capacity. Numerical results obtained from ANSYS Explicit STR FE models are consistent with the experimental results. © 2014, Iran University of Science and Technology. All rights reserved.Item Low velocity impact behavior of RC slabs with different support types(Elsevier Ltd, 2015) Anil Ö.; Kantar E.; Yilmaz M.C.Studies focused on the effects of supporting conditions on the behavior of reinforced concrete slabs subjected to static and dynamic loadings may be found in the literature. However, in the literature no study was found about the effect of variation of the support conditions on the behavior of slabs subjected to impact loads. Consequently, an experimental study was performed on the behavior of reinforced concrete slabs subjected to impact loading. Eight (8) square reinforced concrete slabs with dimensions 500 × 500 × 50 mm were tested by changing two parameters; (i) support type, (ii) support layout. In scope of the experimental study, 4 different support layouts were considered on 2 main support types (i.e. fixed and hinge supports). In the experimental study, impact loadings were applied to the specimens using a drop weight impact test set up. Acceleration-time responses of those specimens were measured by dropping a standard-weighing hammer from a height of 500 mm. Effects of the parameters on the damage distribution, number of drops, acceleration-time, velocity-time and displacement-time responses were investigated. Variations of velocities and displacements were calculated for all specimens by using measured accelerations. Finite element analyses conducted using ANSYS Explicit STR software was used to simulate the experiments. It was observed that the results obtained using the numerical model was in good agreement with those obtained from the experimental study. © 2015 Elsevier Ltd. All rights reserved.Item Experimental and numerical investigation of reinforced concrete beams with variable material properties under impact loading(Elsevier Ltd, 2016) Anil Ö.; Durucan C.; Erdem R.T.; Yorgancilar M.A.In this study, behaviors of reinforced concrete beams manufactured from several concrete types are experimentally and numerically investigated under dynamic impact loading. In the experimental part of the study, 12 beams manufactured using low strength concrete, normal strength concrete and engineered cementitious composites (ECC) containing polyvinyl alcohol (PVA) fibers are tested under dynamic impact loading. The dimensions of the manufactured reinforced concrete beams are also used as a variable to observe the effect of beam size on the behavior under dynamic impact loading. After the experimental study, finite element analyses of the tested beams are also conducted by using commonly used finite element software to observe the stress distribution under the impact loading. The results obtained from the experimental study illustrated that material type significantly affected the width of the observed cracks on the test specimens. Generally the smallest cracks formed on the test specimens manufactured using ECC and the largest cracks formed on the test specimens manufactured using low strength concrete. The results of the finite element study showed that the crack patterns on the test specimens are in good agreement with the stress distributions obtained from the impact loading simulations. © 2016 Elsevier LtdItem Investigation of lateral impact behavior of RC columns(Techno Press, 2018) Anil Ö.; Tuğrul Erdem R.; Tokgöz M.N.Reinforced concrete (RC) columns which are the main vertical structural members are exposed to several static and dynamic effects such as earthquake and wind. However, impact loading that is sudden impulsive dynamic one is the most effective loading type acting on the RC columns. Impact load is a kind of impulsive dynamic load which is ignored in the design process of RC columns like other structural members. The behavior of reinforced concrete columns under impact loading is an area of research that is still not well understood; however, work in this area continues to be motivated by a broad range of applications. Examples include reinforced concrete structures designed to resist accidental loading scenarios such as falling rock impact; vehicle or ship collisions with buildings, bridges, or offshore facilities; and structures that are used in high-threat or high-hazard applications, such as military fortification structures or nuclear facilities. In this study, free weight falling test setup is developed to investigate the behavior effects on RC columns under impact loading. For this purpose, eight RC column test specimens with 1/3 scale are manufactured. While drop height and mass of the striker are constant, application point of impact loading, stirrup spacing and concrete compression strength are the experimental variables. The time-history of the impact force, the accelerations of two points and the displacement of columns were measured. The crack patterns of RC columns are also observed. In the light of experimental results, low-velocity impact behavior of RC columns were determined and interpreted. Besides, the finite element models of RC columns are generated using ABAQUS software. It is found out that proposed finite element model could be used for evaluation of dynamic responses of RC columns subjected to low-velocity impact load. Copyright © 2018 Techno-Press, Ltd.Item Low-velocity impact behaviour of two way RC slab strengthening with CFRP strips(Elsevier Ltd, 2018) Yılmaz T.; Kıraç N.; Anil Ö.; Erdem R.T.; Sezer C.There are a lot of studies focused on behaviour of reinforced concrete (RC) slabs under static and dynamic loadings in the literature. However, investigations related to Carbon Fibre Reinforced Polymer (CFRP) strengthened RC slabs subjected to impact load are still relatively rare. Consequently, an experimental study was performed in order to determine impact behaviour of two way simply supported RC slabs strengthened with CFRP strips. The arrangement and width of CFRP strips were varied in an experimental study. The impact load was applied to slabs using moveable drop-weight test machine designed by the authors. A total of nine RC slabs that were 1000 × 1000 × 80 mm dimensions were manufactured. RC slabs were strengthened using CFRP strips with a width of 50 and 100 mm as orthogonally and diagonally in both one and two directions. One of the specimens was un-strengthened and manufactured as reference specimens. The time-history of the impact force, the accelerations of two points, the center displacement of slabs and the strains of four points on CFRP strips were measured. The crack patterns of slabs are also observed. In the light of experimental results, the effects of applied strengthening method on low-velocity impact behaviour of RC slabs were determined and interpreted. Besides, the finite element models of RC slabs strengthened with CFRP strips are generated using ABAQUS software. It is found out that the proposed finite element model could be used for evaluation of dynamic responses of RC slabs strengthened with CFRP strips subjected to low-velocity impact load. © 2018 Elsevier LtdItem Experimental Investigation of Impact Behaviour of RC Slab with Different Reinforcement Ratios(Springer Verlag, 2020) Yılmaz T.; Kıraç N.; Anil Ö.; Erdem R.T.; Kaçaran G.Reinforced concrete (RC) slabs may be exposed to the low-velocity impact load during their service periods. In low-velocity impact scenarios, the effect of strain rates has been remarkably higher than quasi-static loading because the loading duration is very short. Thus, structural responses and failure modes will be different. The present study aims to investigate dynamic response and failure modes of simply supported two-way RC slabs exposed to low-velocity impact load. In the experimental part of this study, nine RC slabs with the dimension of 1,000 × 1,000 × 80 mm were tested. The reinforcement ratio of RC slabs and the input impact energy applied to RC slabs were experimental variables investigated. A drop-weight test setup was utilized to apply impact load to RC slabs. By varying drop-height as 1,000, 1,250 and 1,500 mm, three different impact energies have been applied to RC slabs via a hammer of which weight is 84 kg. The time histories of the accelerations, displacements and impact loads were recorded. The dynamic responses obtained by tests and the failure modes observed has been interpreted in detail. Besides, a finite element model where explicit dynamic analysis is performed has been established for verification of the experimental results. There was observed good accordance between numerical and experimental results. Consequently, it is considered that the present finite element treatment can be used for the evaluation of the dynamic responses and failure modes of RC slabs exposed to low-velocity impact load. © 2019, Korean Society of Civil Engineers.Item Investigation of impact behavior of reinforced concrete beam to column connection strengthened with carbon fiber-reinforced polymer strips(John Wiley and Sons Inc, 2021) Kaya T.; Aras M.; Yilmaz T.; Çalişkan Ö.; Anil Ö.; Erdem R.T.Reinforced concrete (RC) members may expose to impulsive dynamic loads due to the reasons such as the explosions occurring in the interior or exterior part of them, rockfall, the vehicle crash to the bridges, the collision of masses with the effects of floods and landslide. Many studies have investigated the effects of impulsive dynamic loads on the beam, column, and slab RC structural elements have been investigated in the literature. However, the authors have not encountered any study focused on the impact behavior of beam to column connections of the frames constructing the bearing system of reinforced concrete structures. Therefore, an experimental study has been planned to investigate RC beam impact behavior to column connections strengthened with carbon fiber-reinforced polymer (CFRP) strips. The concrete compressive strength, shear reinforcement spacing, CFRP strip spacing, and input impact energy applied to test specimens were taken as experimental variables. The time histories of impact load acting on test specimens, accelerations, displacements, and the strains measured from CFRP strips have been recorded in experiments. The experimental variables' effect on dynamic responses of RC beam to column connections strengthened with CFRP strips subjected to impact load has been interpreted in detail. The study's scope and improved numerical analysis procedure have also been introduced to verify experimental results. Good agreement between numerical and experimental results demonstrated that the presented numerical procedures could be safely used for evaluation of impact behavior of RC beam to column connections strengthened with CFRP strips. © 2021 International Federation for Structural Concrete.Item Behavior of glulam timber beam strengthened with carbon fiber reinforced polymer strip for flexural loading(SAGE Publications Ltd, 2021) İşleyen Ü.K.; Ghoroubi R.; Mercimek Ö.; Anil Ö.; Erdem R.T.In the last 20 years, the use of wooden structures and their dimensions have gradually increased. The wood application has increased in different structures such as multistory buildings, sports, industrial facilities, road and railway bridges, power transmission lines, and towers. The widespread use and size of wood structures have increased the research on developing special types of wood products supported by composite materials. Laminated wood elements are the leading composite wood materials. Laminated wooden beams allow making much larger openings than standard solid wood structural elements. The development of the sizes and usage areas of wooden structures has increased the capacity of glulam structural elements and reveals the need to improve their performance. Carbon fiber reinforced polymers (CFRPs) are the most suitable options for increasing the bearing capacity values of glulam beams and improving general load–displacement behaviors. In this study, the use of CFRP strips in different layouts to increase glulam wooden beams and the application of CFRP fan-type anchors in the CFRP strip endpoints are the studied variables. Anchored and non-anchored glulam wooden beams reinforced with CFRP strips with different layouts were tested using a three-point bending test. The ultimate load capacity, initial stiffness, displacement ductility ratio, energy dissipation capacity, failure mechanisms, and general load–displacement behavior of wooden beam test specimens were obtained and interpreted as a result of the experiments. © The Author(s) 2021.Item Experimental and numerical investigation of timber formwork beam under different loading type(Taylor and Francis Ltd., 2022) Dönmez T.Ü.; Türer A.; Anil Ö.; Erdem R.T.With the developing construction technologies, the formwork systems used in the manufacturing of the structures have also changed and developed significantly. Especially in the production of high-rise buildings, a special sliding formwork system that is quick-installation, resistant to external loads, can be used more than once, are widely used and preferred. Timber and composite timber materials are preferred due to their durability, ease of installation, lightness compared to steel systems, and easy to use more than one time. Within the scope of this study, it was aimed to investigate the performance and behaviors of timber beams of 1800 and 2450 mm length experimentally under the influence of different loading types in H20 top P-type, which is among the products of DOKA Company. During the use of timber formwork beams, various loading types such as static, fatigue, and sudden dynamic impact load can be affected. For this reason, an experimental study was carried out, and general load-displacement behaviors, initial stiffness, displacement ductility ratios, energy dissipation capacities, collapse mechanisms, acceleration, displacement, and impact load-time behaviors under the effect of monotonic static, repetitive fatigue and impact loading of two different length timber formwork specimens were examined. In addition to experimental study, nonlinear numerical analysis is made by using ABAQUS software for experimental specimens and compared with results with an experimental study. © 2020 Taylor & Francis Group, LLC.Item Experimental and numerical investigation of impact behavior of RC slab with different opening size and layout(Elsevier Ltd, 2022) Yılmaz T.; Anil Ö.; Tuğrul Erdem R.The present study intends to investigate the dynamic responses and failure modes of two-way reinforced concrete (RC) slabs that have openings in different sizes and locations under the impact load effect. RC slabs may include the openings due to the various architectural imperatives. Stair and elevator openings, ventilation openings, the openings left for the electricity, and the water installations can be given as examples of openings taken place in the RC slabs. Many studies related to RC slabs subjected to the static and the reversed-cyclic dynamic loads have existed in the literature. However, at the end of the detailed literature review conducted, the authors have not encountered a comprehensive study focused on the RC slabs' impact behavior that has openings in different sizes and locations. In the present experimental study's scope, the impact loading was applied to two-way RC slabs with the openings via the drop-weight test setup designed by the authors. The time-histories of acceleration and displacements measured from the RC slabs and impact forces acting on the RC slabs have been recorded during the tests to investigate the effect of opening sizes and locations on the RC slabs' impact performance. Furthermore, a finite element model (FEM) has been developed using ABAQUS software to calculate dynamic response and failure modes of the RC slabs with openings. Good agreement between experimental and numerical results has proven that the proposed FEM could be used to evaluate the impact behavior of the RC slabs that have the openings. © 2021 Institution of Structural Engineers